1. Field of the Invention
The present invention relates to a power saving control of a network device and a network system.
2. Description of the Related Art
Various methods for cutting off the power supply of a CPU in a power saving mode have already been put into practical use so as to meet the standards of energy saving, which have been increasingly strict in recent years.
On the other hand, however, a need to rapidly return from a power saving mode to a normal mode is increasing for a network device such as a network-ready printer or multifunction device.
In addition, a size of a program increases in the multifunction device or the like of recent date and cost increase is concerned if all programs are stored in a ROM. Therefore, in some cases a hard disk may be also used as an image storing unit and programs may be stored in a partial area.
However, in this case, the programs are downloaded from the hard disk to a RAM after the device is activated, and then, the programs is executed on the RAM. Therefore, this contradicts the above-described need for rapid return.
Therefore, various methods for cutting off the power supply of a CPU while storing the program expanded on the RAM have been put into practical use.
In addition, transition to the power saving mode may be performed when the operation has not been carried out on an operational panel within a fixed time period and no inquiry and no data reception has been made from other devices on the network. On the other hand, the transition from the power saving mode may also performed when a particular operation is carried out on the operational panel or an inquiry or data reception has been made from any other device on the network.
In Japanese Patent Laid-Open No. 2001-75687, a power management device, which manages a power saving state of a printer or some other device, is notified that the device has transitioned into a sleep mode by a broadcast. On the other hand, upon detecting a service request for the device on a network, the power management device that has received the notification restores the device from the power saving state. This improves the power saving efficiency of the device on the network.
In the conventional art, however, there is a case where a monitoring device and application software for monitoring the state of the device by regularly acquiring state information for the device are located on the network. In such a case, due to an inquiry of monitoring transmitted from a monitoring device or the like, the device is unable to transition to the power saving mode. Alternatively, there is a problem such that the device is immediately restored from the power saving mode due to the above inquiry even if the device is able to transition to the power saving mode.
The periodic monitoring inquiries can be problematic when there are many devices and application software for monitoring the state of a network device (e.g., network-ready printer, multifunction image forming device).